Thursday, August 4, 2011

The Coelacanths of Kansas

Most everyone is aware of the story of the "living fossil" fish, the coelacanth. One was caught off the coast of Africa in the 1930s, surprising everyone since they were thought to have gone extinct at the end of the Cretaceous period along with the dinosaurs. Today there is but one genus left, Latimeria. They are strange animals, even for people experienced in working with fish.

Cast of the extant coelacanth Latimeria in the RMDRC
We recovered and prepared 2 specimens of the giant coelacanth Megalocoelacanthus from western Kansas in the past decade. As far as I know they are the only two examples of this big coelacanth ever recovered from the Niobrara chalk. The first specimen was excavated from the lower chalk around MU5 (Coniacian age) is fairly complete, and will be our basis for a 3d reconstruction of the skull and body. The second specimen was a fragmented left lower jaw found in the upper chalk, under MU20, putting it early Campanian in age. We used the coronoid from this specimen in our reconstruction to replace the missing one from the first.

About 20% of the skull material found with our first Megalocoelacanthus
Someone once said "go big or go home". We're taking that to heart as our first reconstruction will consist of a 3d skull on a panel-mounted restoration of the body. We're basing the postcranial skeleton heavily on Latimeria, since we only have a few parts of the pectoral and dorsal fins. Coelacanths don't have ossified vertebrae (or ribs for that matter) meaning skulls and fins are about all you are ever going to find.

RMDRC sculptor Mary working on our prototype
Our specimen is truly going to be a giant, coming in at about 9 feet 4 inches (3m) in length. As far as I can tell this will also be the very first restoration attempt of Megalocoelacanthus. Of course we'll be molding the thing, so hopefully it can be placed in museums worldwide. Ours isn't the largest specimen ever found, but it sure seems it is by far the most complete.

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